*4.7. Firmness Measurement*

The firmness of the fresh-cut purple sweet potato samples was measured using a texture analyzer (Compac-100, Scientific Co., Tokyo, Japan) equipped with a 3 mm cylinder probe was used to assess the hardness of a fresh-cut purple sweet potato. A puncture test was carried out on a horizontally-positioned sample over a 13 mm hole at the speed of 60 mm/min and a travel distance of 20 mm [3]. The maximum force required to penetrate the sample was recorded for seven randomly selected fresh-cut PFSP per treatment group.
